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path: root/drivers/spi/spi-rspi.c
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2017-02-19Merge remote-tracking branches 'spi/topic/rockchip', 'spi/topic/rspi', ↵Mark Brown1-3/+1
'spi/topic/s3c64xx', 'spi/topic/sh-msiof' and 'spi/topic/slave' into spi-next
2017-02-16spi: rspi: Replaces "n" by "len" in qspi_transfer_*()DongCV1-2/+2
This patch replaced "n" by "len" bytes of data in qspi_transfer_in() and qspi_transfer_out() function. This will make improving readability. Signed-off-by: DongCV <cv-dong@jinso.co.jp> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@kernel.org>
2017-02-16spi: rspi: Fixes bogus received byte in qspi_transfer_in()DongCV1-1/+0
In qspi_transfer_in(), when receiving the last n (or len) bytes of data, one bogus byte was written in the receive buffer. This code leads to a buffer overflow. "jffs2: jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x03b40000: 0x1900 instead jffs2: jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x03b40004: 0x000c instead" The error message above happens when trying to mount, unmount, and remount a jffs2-formatted device. This patch removed the bogus write to fixes: 3be09bec42a800d4 "spi: rspi: supports 32bytes buffer for DUAL and QUAD" And here is Geert's comment: "spi: rspi: Fix bogus received byte in qspi_transfer_in() When there are less than QSPI_BUFFER_SIZE remaining bytes to be received, qspi_transfer_in() writes one bogus byte in the receive buffer, possibly leading to a buffer overflow. This can be reproduced by mounting, unmounting, and remounting a jffs2-formatted device, causing lots of warnings like: "jffs2: jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x03b40000: 0x1900 instead" Remove the bogus write to fix this. " Signed-off-by: DongCV <cv-dong@jinso.co.jp> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@kernel.org>
2017-01-04spi: rspi: Remove useless memory allocation failure messageGeert Uytterhoeven1-3/+1
Printing an error on memory allocation failure is unnecessary. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-11-09spi: rspi: avoid uninitialized variable accessArnd Bergmann1-49/+45
The newly introduced rspi_pio_transfer_in_or_our() function must take either a valid 'rx' or 'tx' pointer, and has undefined behavior if both are NULL, as found by 'gcc -Wmaybe-unintialized': drivers/spi/spi-rspi.c: In function 'rspi_pio_transfer_in_or_our': drivers/spi/spi-rspi.c:558:5: error: 'len' may be used uninitialized in this function [-Werror=maybe-uninitialized] The analysis of the function is correct in principle, but the code is currently safe because both callers always pass exactly one of the two pointers. Looking closer at this function shows that having a combined method for rx and tx here actually increases the complexity and the size of the file. This simplifies it again by keeping the two separate, which then ends up avoiding that warning. Fixes: 3be09bec42a8 ("spi: rspi: supports 32bytes buffer for DUAL and QUAD") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-11-04spi: rspi: supports 32bytes buffer for DUAL and QUADHiep Cao Minh1-3/+49
This patch supports 32bytes of buffer for DUAL and QUAD in QSPI by Using Transmit/Receive Buffer Data Triggering Number. In order to improve the DUAL and QUAD's performance of SPI while transferring data in PIO mode, it sends/receives each 32bytes data instead of each byte data as current situation. Signed-off-by: Hiep Cao Minh <cm-hiep@jinso.co.jp> Signed-off-by: Mark Brown <broonie@kernel.org>
2016-08-08spi: rspi: Increase accuracy of bit rate for RZChris Brandt1-2/+12
When you leave the clock divider at 0, 130kHz is the lowest you can go. Also, by adjusting the clock divider you can get more accurate resolutions for clock speeds lower than 16MHz. This patch uses the clock divider as part of the bit rate setup. Signed-off-by: Chris Brandt <chris.brandt@renesas.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-07-03spi: rspi: Make qspi_set_send_trigger() return "unsigned int"Geert Uytterhoeven1-2/+4
qspi_set_send_trigger() returns an unsigned value, so make it return "unsigned int". Update the loop variables qspi_trigger_transfer_out_int() to match the above. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-07-03spi: rspi: Drop variable "error" in qspi_trigger_transfer_out_in()Geert Uytterhoeven1-7/+6
Just use "ret" instead, for consistency with other similar functions. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-06-02spi: rspi: Re-do the returning value of qspi_transfer_out_inHiep Cao Minh1-5/+1
To reduce complexity of code, drop "ret" then qspi_transfer_out_in function should return the value of "qspi_trigger_transfer_out_in" directly. Signed-off-by: Hiep Cao Minh <cm-hiep@jinso.co.jp> Acked-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-06-02spi: rspi: modify the name of "qspi_trigger_transfer_out_int" functionHiep Cao Minh1-2/+2
The name of "qspi_trigger_transfer_out_int" function should be "qspi_trigger_transfer_out_in" without "t". Signed-off-by: Hiep Cao Minh <cm-hiep@jinso.co.jp> Acked-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-05-07spi: rspi: Re-do the returning value of rspi_dma_check_then_transferHiep Cao Minh1-8/+5
To reduce indentation and complexity of code, insteeds of returning zero the function rspi_dma_check_then_transfer should return rspi_dma_transfer directly after checking error. Signed-off-by: Hiep Cao Minh <cm-hiep@jinso.co.jp> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-05-01spi: rspi: Constify platform_device_idKrzysztof Kozlowski1-1/+1
The platform_device_id is not modified by the driver and core uses it as const. Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-04-24Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dmaLinus Torvalds1-1/+0
Pull slave-dmaengine updates from Vinod Koul: - new drivers for: - Ingenic JZ4780 controller - APM X-Gene controller - Freescale RaidEngine device - Renesas USB Controller - remove device_alloc_chan_resources dummy handlers - sh driver cleanups for peri peri and related emmc and asoc patches as well - fixes and enhancements spread over the drivers * 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma: (59 commits) dmaengine: dw: don't prompt for DW_DMAC_CORE dmaengine: shdmac: avoid unused variable warnings dmaengine: fix platform_no_drv_owner.cocci warnings dmaengine: pch_dma: fix memory leak on failure path in pch_dma_probe() dmaengine: at_xdmac: unlock spin lock before return dmaengine: xgene: devm_ioremap() returns NULL on error dmaengine: xgene: buffer overflow in xgene_dma_init_channels() dmaengine: usb-dmac: Fix dereferencing freed memory 'desc' dmaengine: sa11x0: report slave capabilities to upper layers dmaengine: vdma: Fix compilation warnings dmaengine: fsl_raid: statify fsl_re_chan_probe dmaengine: Driver support for FSL RaidEngine device. dmaengine: xgene_dma_init_ring_mngr() can be static Documentation: dma: Add documentation for the APM X-Gene SoC DMA device DTS binding arm64: dts: Add APM X-Gene SoC DMA device and DMA clock DTS nodes dmaengine: Add support for APM X-Gene SoC DMA engine driver dmaengine: usb-dmac: Add Renesas USB DMA Controller (USB-DMAC) driver dmaengine: renesas,usb-dmac: Add device tree bindings documentation dmaengine: edma: fixed wrongly initialized data parameter to the edma callback dmaengine: ste_dma40: fix implicit conversion ...
2015-04-06spi: signedness bug in qspi_trigger_transfer_out_int()Dan Carpenter1-1/+1
We need "ret" to be unsigned for the error handling to work. The signedness of "i" and "n" don't matter but qspi_set_send_trigger() returns an int so I've changed them to int as well. Fixes: 4b6fe3edcbba ('spi: Using Trigger number to transmit/receive data') Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-30spi: Using Trigger number to transmit/receive dataHiep Cao Minh1-7/+117
In order to transmit and receive data when have 32 bytes of data that ready has prepared on Transmit/Receive Buffer to transmit or receive. Instead transmits/receives a byte data using Transmit/Receive Buffer Data Triggering Number will improve the speed of transfer data. Signed-off-by: Hiep Cao Minh <cm-hiep@jinso.co.jp> Signed-off-by: Mark Brown <broonie@kernel.org>
2015-02-23spi: rspi: remove slave_id settings for DMAEngineArnd Bergmann1-1/+0
Current rspi sets dma_slave_config :: slave_id field for DMAEngine, but it is no longer needed. Let's remove it. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Acked-by: Mark Brown <broonie@kernel.org> Acked-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-12-22spi: Remove FSF mailing addressesJarkko Nikula1-5/+0
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Mark Brown <broonie@kernel.org>
2014-10-20spi: drop owner assignment from platform_driversWolfram Sang1-1/+0
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-08-28spi: rspi: Add support for new R-Car Gen2 SoCsGeert Uytterhoeven1-1/+1
Add support for QSPI in: - r8a7792 (R-Car V2H) - r8a7793 (R-Car M2-N) - r8a7794 (R-Car E2) r8a7791 is now called "R-Car M2-W". Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-17spi: rspi: Add DT support to DMA setupGeert Uytterhoeven1-14/+23
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-17spi: rspi: Configure DMA slave bus width to 8 bitGeert Uytterhoeven1-2/+5
The new Renesas R-Car Gen2 DMA Controller driver (rcar-dmac) requires explicit configuration of the DMA slave bus width. Hardcode the DMA transfer size to 1 byte for both directions, as that's the only supported configuration (16-bit DMA support was removed in commit 9c5de2c1754c2bb3c69c4d7bf0d0edc0a61d8232 ("spi: rspi: Remove unused 16-bit DMA support")). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-17spi: rspi: Use devm_kasprintf()Geert Uytterhoeven1-4/+3
Use the devm_kasprintf() helper function instead of open coding error-prone buffer handling and string formatting. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-17spi: rspi: Remove unneeded semicolonGeert Uytterhoeven1-1/+1
Introduced by commit 426ef76dd8a394a0e04d096941cd9acb49539a3e ("spi: rspi: Add DT support"). Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-17spi: rspi: Fix leaking of unused DMA descriptorsGeert Uytterhoeven1-36/+58
If dmaengine_prep_slave_sg() or dmaengine_submit() fail, we may leak unused DMA descriptors. As per Documentation/dmaengine.txt, once a DMA descriptor has been obtained, it must be submitted. Hence: - First prepare and submit all DMA descriptors, - Prepare the SPI controller for DMA, - Start DMA by calling dma_async_issue_pending(), - Make sure to call dmaengine_terminate_all() on all descriptors that haven't completed. Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-07-17spi: rspi: Handle dmaengine_prep_slave_sg() failures gracefullyGeert Uytterhoeven1-8/+22
As typically a shmobile SoC has less DMA channels than devices that can use DMA, we may want to prioritize access to the DMA channels in the future. This means that dmaengine_prep_slave_sg() may start failing arbitrarily. Handle dmaengine_prep_slave_sg() failures gracefully by falling back to PIO. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-07-07spi: rspi: Pass spi_master pointer to rspi_release_dma()Geert Uytterhoeven1-7/+7
rspi_release_dma() doesn't need access to any fields in the driver private data, except for the pointer to the SPI master object. Hence just pass the needed pointer. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-07-07spi: rspi: Remove unused variable in rspi_rz_transfer_one()Geert Uytterhoeven1-1/+0
Introduced by commit 8b983e90ea1a3dd82070f96c062ad521a06b7cc0 ("spi: rspi: Extract rspi_common_transfer()"), which removed its users. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Extract rspi_common_transfer()Geert Uytterhoeven1-37/+24
Extract the common parts of rspi_transfer_one(), rspi_rz_transfer_one(), and qspi_transfer_out_in() into the new function rspi_common_transfer(). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Add DMA support for RSPI on RZ/A1HGeert Uytterhoeven1-0/+3
Enable DMA support for RSPI on r7s72100 (RZ/A1H). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Add DMA support for QSPI on R-Car Gen2Geert Uytterhoeven1-0/+9
Enable DMA support for QSPI on R-Car Gen2, for Single, Dual, and Quad SPI Transfers. Performance figures for reading from a QSPI FLASH driven at 24.375 MHz on r8a7791/koelsch: - Single: 1.1 Mbps PIO, 23 Mbps DMA - Dual : 12.7 Mbps PIO, 48 Mbps DMA - Quad : 13 Mbps PIO, 70 Mbps DMA Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Absorb rspi_rz_transfer_out_in() into rspi_rz_transfer_one()Geert Uytterhoeven1-11/+4
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Merge rspi_*_dma() into rspi_dma_transfer()Geert Uytterhoeven1-78/+61
rspi_send_dma() and rspi_send_receive_dma() are very similar. Consolidate into a single function rspi_dma_transfer(), and add missing checks for dmaengine_submit() failures. Both sg_table pointer parameters can be NULL, as RSPI supports TX-only mode, and unidirectional DMA transfers will also be needed later for Dual/Quad DMA support. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Pass sg_tables instead of spi_tranfer to rspi_*_dma()Geert Uytterhoeven1-10/+12
The DMA routines only need access to the scatter-gather tables inside the spi_transfer structures, hence just pass those. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Move RSPI-specific setup out of DMA routinesGeert Uytterhoeven1-20/+10
Refactor RSPI (on SH) DMA handling to make it reusable for other RSPI implementations: - Call the DMA routines after configuring the TX Mode bit and after calling rspi_receive_init(), so these RSPI-specific operations can be removed from the DMA routines, - Absorb rspi_transfer_out_in() into rspi_transfer_one(). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Use SPI core DMA mapping frameworkGeert Uytterhoeven1-90/+50
Use the SPI core DMA mapping framework instead of our own. If available, DMA is used for transfers larger than the FIFO size (8 or 32 bytes). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: SPI DMA core needs both RX and TX DMA to functionGeert Uytterhoeven1-22/+14
The SPI DMA core framework needs both RX and TX DMA to function. As a preparation for converting the driver to use this framework, fall back to PIO if no DMA channel or only one DMA channel is available. This affects only RSPI, which could do DMA transfers for TX-only before. RSPI-RZ and QSPI (at least for Single SPI Transfers) will need both RX and TX DMA anyway. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Remove unneeded resource test in DMA setupGeert Uytterhoeven1-12/+9
The resource is know to exist, as rspi_probe() already mapped it. Remove the test, and just pass the resource. Pass the device pointer instead of the platform device pointer, as the latter is no longer needed. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Extract rspi_request_dma_chan()Geert Uytterhoeven1-34/+55
Setup of the receive and transmit DMA channels is very similar, so let's consolidate. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Don't consider DMA configuration failures fatalGeert Uytterhoeven1-4/+2
Fall back to PIO if DMA configuration failed. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Extract rspi_pio_transfer()Geert Uytterhoeven1-62/+33
The various PIO loops are very similar. Consolidate into a single function rspi_pio_transfer(). Both buffer pointers can be NULL, as RSPI supports TX-only mode, and Dual/Quad SPI Transfers are unidirectional. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Use core SPI_MASTER_MUST_[RT]X handlingGeert Uytterhoeven1-74/+58
RSPI needs dummy transfers to generate the SPI clock on receive. RSPI-RZ and QSPI always do both transmit and receive. Use the SPI core SPI_MASTER_MUST_RX/SPI_MASTER_MUST_TX infrastructure instead of checking for the presence of buffers and providing dummy data ourselves (for PIO), or providing a dummy buffer (for DMA). rspi_receive_dma() now provides full duplex DMA transfers on RSPI, and is renamed to rspi_send_receive_dma(). As the SPI core will always provide a TX buffer, the logic to choose between DMA send and DMA send/receive in rspi_transfer_one() now has to check for the presence of an RX buffer. Likewise for the DMA availability tests in rspi_is_dma(). The buffer tests in qspi_transfer_one() are now always true, so they're removed. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Remove unused 16-bit DMA supportGeert Uytterhoeven1-78/+6
The 16-bit DMA support doesn't fit well within the SPI core DMA framework, as it needs to manage its own double-sized temporary buffers, for handling the interleaved data. Remove it, as there is no in-tree board code that sets rspi_plat_data.dma_width_16bit. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Do not call rspi_receive_init() for TX-onlyGeert Uytterhoeven1-4/+4
Since commit 8449fd76deb9ac67a15a6fb8ead7bb4595d019d2 ("spi: rspi: Merge rspi_send_pio() and rspi_receive_pio()"), rspi_receive_init() is called for transmit-only transfers too, while this is not needed. Only call rspi_receive_init() when receiving, to preserve behavior on RSPI on SH. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-06-02spi: rspi: Extract rspi_wait_for_{tx_empty,rx_full}()Geert Uytterhoeven1-8/+21
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-05-26spi: rspi: Round up division to avoid slave overclockingGeert Uytterhoeven1-3/+5
The calculation of the bit rate divider used a standard C division, which rounds down the quotient. This may lead to a higher bitrate than requested. Round up to avoid this. E.g. on Koelsch, the SPI flash (configured for 30 MHz) was driven at 48.75 MHz. After this patch it's driven at a safe 24.375 MHz. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-03-11spi: rspi: Add runtime PM support, using spi core auto_runtime_pmGeert Uytterhoeven1-7/+5
Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-23spi: rspi: Fix loopback mode for Dual/Quad SPI TransfersGeert Uytterhoeven1-1/+3
While normal Dual and Quad SPI Transfers are unidirectional, we must do a bidirectional transfer if loopback mode is enabled, else rx_buf is not filled. With spidev it seemed to work, as spidev uses the same buffer for tranmission and reception. Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-23spi: rspi: Remove empty rspi_cleanup()Geert Uytterhoeven1-5/+0
If spi_master.cleanup() is not needed, it can be left unimplemented. Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-04spi: rspi: Only enable interrupts when there's a need to waitGeert Uytterhoeven1-0/+3
rspi_wait_for_interrupt() unconditionally enables interrupts, even when the wait condition is already satisfied. This causes a high interrupt load (2 interrupts/byte for full-duplex Single SPI transfers, 1 interrupt/byte for RSPI with TX Only mode, or QSPI in unidirectional Dual or Quad Transfer mode). Change this to return immediately when the wait condition is satisfied. This dramatically reduces the interrupt load, especially in high-speed Quad Transfer mode, and increases transfer speed, as no interrupts need to be handled when there's space available in the output FIFO, or data available in the input FIFO. Benchmark results for QSPI on r8a7791 while reading 1 MiB from 30 MHz SPI FLASH on the Koelsch development board: Before: Single SPI Dual SPI Quad SPI Interrupts: 2096856 1048592 1048594 Mbps: 0.9 1.6 1.6 After: Single SPI Dual SPI Quad SPI Interrupts: 1048569 21295 8 Mbps: 0.7 10.8 12.9 I don't know why Single SPI slowed down a bit. I've also verified functionality for RSPI-RZ on r7s72100, but don't have benchmark results as there's no SPI FLASH connected to RSPI on the Genmai development board. Unlike RSPI and QSPI, RSPI-RZ has separate interrupts for RX and TX, which shows that Single SPI transfers now generate (mostly) RX interrupts, as expected. Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org> Signed-off-by: Mark Brown <broonie@linaro.org>
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